Preparation and electrochemical performance study of high-performance nitrogen-doped activated carbon derived from biomass mangosteen shell

Abstract High-performance porous carbon electrode materials for supercapacitors were successfully fabricated using mangosteen peel as a biomass-derived carbon source. The synthesis involved KOH activation combined with urea-based nitrogen doping and ammonium dihydrogen phosphate-mediated N-P dual-doping strategies. The incorporation of nitrogen and phosphorus heteroatoms was found to effectively modulate the pore structure of the carbon material while significantly enhancing its surface wettability and charge transfer kinetics. Structural characterization via x-ray diffraction (XRD), scanning electron microscopy (SEM), and N 2 adsorption–desorption confirmed that the obtained activated carbon possesses a three-dimensional hierarchical porous structure with a high specific surface area of 1279.611 m 2 g −1 . Electrochemical testing in a three-electrode system with 6 mol l −1 KOH electrolyte revealed excellent energy storage performance, exhibiting an areal specific capacitance of 4.28 F cm −2 at 1 mA cm −2 . Remarkably, even at a 50-fold higher current density (50 mA cm −2 ), the material maintained a capacitance retention rate of 98% (3 F cm −2 ), demonstrating outstanding rate capability. By systematically investigating the synergistic effects of activators and dopants, this study provides valuable insights into the structural design and performance optimization of biomass-derived carbon materials for advanced supercapacitor applications.